Unfortunately it still isn’t running. But the demo below makes us think that he’s really close. Timing is always touchy and that seems to be what is causing the problems. He makes use of a lot of plumbing fixtures. At the right you can see the parts (including a peanut butter jar) which make his carburetor with a valve pointing straight up as the choke. The fuel and air mixture moves down through the pipe to the cylinder and valve assembly where it is ignited by the black grill igniter module. His custom cut plywood gear moves with the fly-wheel. It triggers his improvised spark plug by using a bit of wire to pull on the leaf switch.

We feel like he’s so close to getting this up and running. If you have any advice on where he might be going wrong [Lou] welcomes your input.

[José Manuel Hermo Barreiro] has spent many many hours crafting these tiny engines from hand. Every single piece is custom made specifically for the engine it is going onto. He has created aircraft engines, car engines, and marine engines that all actually run and are the smallest of their kind in the world.

At one point in this video he stands in a room with several engines lined up, all running smoothly and considers that there are possibly over 15,000 hours of work right there in front of him.

If you’re looking for a way to let the kids get hand-ons with science this is a perfect example of how to do it. [Erich] wanted to help out with his 7-year-old’s science project. They decided to build a working model of a steam engine but couldn’t find online instructions appropriate for the age group. So the two of them not only pulled off the build, but then they wrote a guide for others to follow. The thing about it is, you really have to understand a concept to teach it to someone else. So we think the write-up is equally important to having actually done the experiment.

Steam can scald you if you’re not careful. But you don’t really need steam to explore the concepts of a steam engine. The main reason to use steam is that it’s a fairly rudimentary way to build pressure which can be converted to motion. For this demonstration the blue balloon provides that pressure. It’s feeding a reservoir that connects to the valve built out of straws. A plastic piston inside pushes against the crank shaft, spinning the cardboard wheel on the left. When the piston travels past the valve opening it releases the air pressure until the machine makes a revolution and is in place for the next push. This is well demonstrated in the clip after the break.

For as much as we enjoy rockets, explosives, and other dangerous things, we haven’t said a word about the works of [Richard Nakka]. He’s the original hacker rocketeer with thousands of words dedicated to the craft of making things move straight up really fast. One of his more interesting builds is his series on building rocket engines out of PVC pipe written in conjunction with [Chuck Knight].

For the propellent grains, the PVC rocket didn’t use the usual potassium nitrate and sugar mixture of so many homebrew solid rockets. Instead, it uses Sorbitol, an artificial sweetener. While melting and casting the Sorbitol-based propellant grains is much easier than a sugar-based concoction, the Sorbitol had much less thrust than a typical sugar rocket, making it the perfect candidate for a PVC engine.

For those of you wondering about the strength of a PVC engine casing, [Richard] does say making larger rocket engines out of 2 or 3-inch PVC may not make much sense due to the increased chamber pressures. There is a fairly clever reinforcement method for these PVC rockets (PDF warning) that involves using PVC couplers, but the experiments into the strength of these casings have yet to undertaken.

Let’s face it, you’ll never break the motorcycle land speed record without a stellar engineering team and some serious corporate sponsorship. But this build proves that individuals can still set other speed records. [Colin Furze] rode his motorized baby carriage over the 53 mile per hour mark to set a the world’s record. We were surprised to learn it only took him about one month and $750 to build the infant death machine.

The design appears to take a page from the commercial lawnmower industry. We say that because the driver rides along on a little tow dolly behind the carriage itself. All of the controls are mounted within easy reach of the T-bar steering mechanism. There are a couple of rockers for his thumbs which actuate the gas and brakes. Red push buttons just below the handlebars are used for up and down shifting with a third button used as a kill switch. The only thing missing from the write up is video footage of the actual 53mph run. We guess you’ll just have to take his word for it.

We realize the transmission fluid of an automobile’s automatic transmission is used to transfer the power from the engine to the drive shaft. But after watching this Department of Defense video from 1954 we now have a full understanding of the principles involved in fluid coupling. Like us, you probably have seen a diagram of a transmission which shows the fan-like blades that are affected by the moving fluid. But it’s worth watching the 12-minute clip after the break to understand how that liquid is moving and why that matters so much in the design. The motion of the rotors, along with the design of the enclosure, causes the fluid to move in a continual corkscrew — the shape of slinky whose ends have been attached to each other. This type of illustration leads to an intuitive understanding of how it’s possible to facilitate an efficient power transfer using a liquid.

Check out some of the comments left in the Reddit thread regarding this film. We agree with [Runxctry]; there’s something about the format of the presentation that makes these informative and engaging to an almost addictive level. But maybe it’s just the engineering geek deep inside that’s cause these feelings?

You can build a surprising amount of stuff from parts you can pick up at a hardware store. Sometimes, though, getting a project built from sections of pipe is very, very difficult. That’s the case with [Lou]’s hardware store engine: despite an inordinate amount of cleverness, he just can’t seem to get an engine made from pipe fitting to work and is now asking for some ideas from other ingenious makers.

The engine uses regular oxygen and propane tanks you can pick up at Home Depot with torch heads soldered onto half inch pipe. The fuel and oxygen are mixed in a T fitting until a grill igniter sets the gas mixture ablaze pushing a cylinder down the length of a copper pipe. The cylinder is attached to an aluminum flywheel that also controls the opening and closing of the oxygen and propane valves as well as switching the grill igniter on and off.

Right now, [Lou] can get the engine running, but only for one stroke of the cylinder. He’s having a bit of a problem turning this into a working motor. If you’ve got any idea on how to make [Lou]’s engine work, drop a line in the comments. We’ll throw our two cents in and say he needs a valve on the exhaust, but other suggestions are always welcome.